Synthesis and photocatalytic properties of visible-light-responsive, three-dimensional, flower-like La–TiO2/g-C3N4 heterojunction composites

Double-Shelled Porous g-C3 N4 Nanotubes Modified with Amorphous Cu-Doped FeOOH Nanoclusters as 0D/3D Non-Homogeneous Photo-Fenton Catalysts for Effective Removal of Organic Dyes

Graphite phased carbon nitride (g-C₃ N₄ ) has attracted extensive attention attributed to its non-toxic nature, remarkable physical-chemical stability, and visible light response properties. Nevertheless, the pristine g-C₃ N₄ suffers from the rapid photogenerated carrier recombination and unfavorable specific surface area, which greatly limit its catalytic performance. Herein, 0D/3D Cu-FeOOH/TCN composites are constructed as photo-Fenton catalysts by assembling amorphous Cu-FeOOH clusters on 3D double-shelled porous tubular g-C₃ N₄ (TCN) fabricated through one-step calcination. Combined density functional theory (DFT) calculations, the synergistic effect between Cu and Fe species could facilitate the adsorption and activation of H₂ O₂ , and the separation and transfer of photogenerated charges effectively. Thus, Cu-FeOOH/TCN composites acquire a high removal efficiency of 97.8%, the mineralization rate of 85.5% and a first-order rate constant k = 0.0507 min^-1 for methyl orange (MO) (40 mg L^-1 ) in photo-Fenton reaction system, which is nearly 10 times and 21 times higher than those of FeOOH/TCN (k = 0.0047 min^-1 ) and TCN (k = 0.0024 min^-1 ), respectively, indicating its universal applicability and desirable cyclic stability. Overall, this work furnishes a novel strategy for developing heterogeneous photo-Fenton catalysts based on g-C₃ N₄ nanotubes for practical wastewater treatment.

Photocatalysis of TiO2 Sensitized with Graphitic Carbon Nitride and Electrodeposited Aryl Diazonium on Screen-Printed Electrodes to Detect Prostate Specific Antigen under Visible Light

We report on a photoelectrochemical (PEC) device to detect prostatic-specific antigen (PSA) under visible LED light irradiation within the point-of-care (POC) paradigm. The device consists of a 3D printed miniaturized photoelectrochemical system and a disposable PEC immunosensor made with screen-printed carbon electrodes (SPCEs). The SPCEs were coated with nickel single atoms anchored on graphitic carbon nitride (Ni-gC₃N₄), titanium dioxide nanoparticles (TiO₂), and aryl diazonium salt prepared from p-aminobenzoic acid. The electrodeposited aryl diazonium on Ni-gC₃N₄/TiO₂ decreased the recombination of photogenerated charge carriers, leading to a 3.1-fold increase in the photocurrent compared to pure TiO₂. This functionalization strategy provides carboxylic groups to anchor antibodies via the carbodiimide reaction, which may be extended to any other type of immunosensor. Under optimal conditions, the PEC immunosensor was able to detect PSA from 10^-16 to 10^-8 g mL^-1 with a detection limit of 0.06 fg mL^-1. The device robustness was confirmed with reproducibility and stability tests. PSA could also be detected in human serum samples, which demonstrates the potential of the PEC immunosensor for clinical diagnosis.

High Photocatalytic Activity of g-C3N4/La-N-TiO2 Composite with Nanoscale Heterojunctions for Degradation of Ciprofloxacin

Ciprofloxacin (CIP) in natural waters has been taken as a serious pollutant because of its hazardous biological and ecotoxicological effects. Here, a 3D nanocomposite photocatalyst g-C₃N₄/La-N-TiO₂ (CN/La-N-TiO₂) was successfully synthesized by a simple and reproducible in-situ synthetic method. The obtained composite was characterized by XRD, SEM, BET, TEM, mapping, IR, and UV-vis spectra. The photocatalytic degradation of ciprofloxacin was investigated by using CN/La-N-TiO₂ nanocomposite. The main influential factors such as pH of the solution, initial CIP concentration, catalyst dosage, and coexisting ions were investigated in detail. The fastest degradation of CIP occurred at a pH of about 6.5, and CIP (5 mg/L starting concentration) was completely degraded in about 60 min after exposure to the simulated solar light. The removal rates were rarely affected by Na⁺ (10 mg·L⁻¹), Ca²⁺ (10 mg·L⁻¹), Mg²⁺ (10 mg·L⁻¹), and urea (5 mg·L⁻¹), but decreased in the presence of NO₃⁻ (10 mg·L⁻¹). The findings indicate that CN/La-N-TiO₂ nanocomposite is a green and promising photocatalyst for large-scale applications and would be a candidate for the removal of the emerging antibiotics present in the water environment.

Novel La(OH)3-integrated sGO-Ag3VO4/Ag nanocomposite as a heterogeneous photocatalyst for fast degradation of agricultural and industrial pollutants

The composite described couples the benefits of hydroxyl radical formation from sunlight-inactive La(OH)₃ and strong sunlight absorption by Ag₃VO₄.

Enhanced reduction and oxidation capability over the CeO2/g-C3N4 hybrid through surface carboxylation: performance and mechanism

The charge separation efficiency of the CeO₂/g-C₃N₄ heterojunction was greatly enhanced through surface carboxylation of the g-C₃N₄ substrate.

Synthesis of 3D flower-like structured Gd/TiO2@rGO nanocomposites via a hydrothermal method with enhanced visible-light photocatalytic activity

In this study, novel Gd/TiO₂@rGO (GTR) nanocomposites with high photocatalytic performance were fabricated via a one-pot solvothermal approach. During the preparation step, graphene oxide (GO) was reduced to reduced graphene oxide (rGO), and subsequently, on the surfaces of which anatase TiO₂ doped with Gd metal was grown in situ with a 3D petal-like structure. Gd doping into the classical TiO₂@rGO system efficiently expands the absorption range of light, improves the separation of photogenerated electrons, and increases the photocatalytic reaction sites. The specific surface areas, morphological structures, and valence and conduction bands of the obtained GTR nanocomposites were analyzed and correlated with their enhanced photocatalytic performances for the degradation of an aqueous RhB solution. The experimental results indicated that the best performance was achieved with the 3% GTR composite, which exhibited the highest photoelectrocatalytic activity because of two aspects: the rapid separation of electrons and holes, and improvement in adsorption capacity. As compared with pure TiO₂, the GTR composites demonstrated enhanced photoactivity due to synergetic effects between the effective photo-induced electron transfer from TiO₂ to the surface of the rGO acceptor through interfacial interactions and the variation of structure and electrons under the adoption of Gd.

One-pot green synthesis of 3D flower-like structured Gd/TiO₂@rGO nanocomposites via a hydrothermal method with high photocatalytic activity.